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• Overlaying one video on another one and making black pixels or green pixels transparent

  30 décembre 2017, par kostya572

  I found great answer here : https://stackoverflow.com/a/38581696/2337706

  It works only for black pixels. The result is not perfect. I guess if change the overlay background color to other color, e.g. green, red, blue the results would be better. How can I change the other background color ?

  Here is my working code :

  ffmpeg -y \
  
      -i video.webm -i overlay.mov \
  
      -filter_complex " \
  
          [0:v]setpts=PTS-STARTPTS[base]; \
  
          [1:v]crop=iw:0.50*ih,setpts=PTS-STARTPTS+0/TB, \
  
                   format=yuva420p,colorchannelmixer=aa=0.7[overlay]; \
  
       [base][overlay]overlay=x=(W-w)/2:y=0[v]" \
  
   -map "[v]" -map 0:a -c:a copy -c:v libvpx-vp9 -lossless 1 -threads 4 -quality realtime \
  
   -speed 8 -tile-columns 6 -frame-parallel 1 -vsync 2 -shortest output.webm

  The result :
  

  Need result :
  

  Or need result (if impossible first with good quality) :
  

  Thank you, sorry for the frequent questions on ffpmpeg topic.

• Black screen when recording specific screen / window using ffmpeg [closed]

  16 mai, par Mark Brin

  Issue :
I'm trying to capture the specific window using ffmpeg & i've tried these below command for that :

  


  ffmpeg -f gdigrab -framerate 30 -i title="Window Title" -b:v 3M -pix_fmt yuv420p output_FILENAME.webm


  


  And also try changing output format to .mp4

  


  ffmpeg -f gdigrab -framerate 30 -i title="Window Title" -b:v 3M -pix_fmt yuv420p output_FILENAME.mp4


  


  but the output video just shows the black screen with cursor.

  


  What i've tried :

  


  


  • Tried online solutions like Recording Screen with FFmpeg, How to record a specific window using ffmpeg ?, Record specific window using ffmpeg, but none of them worked.

    


  


  • even tried some of the tweaks like removing flags like -pix_fmt yuv420p also tried -f d3d11grab but didn't work.

    


  


  • When i try desktop capture it works completely fine.

    


  


  • I'm using this command to confirm that i'm using correct window title

    


  


  


  Get-Process |
  Where-Object { $_.MainWindowTitle -ne "" } |
  Select-Object -Unique MainWindowTitle


  


  System I'm using :

  


  Windows 11

  


• using X264 and librtmp to send live camera frame, but the flash can't show

  9 mai 2016, par brian_wang

  I am using X264 and librtmp to send my live camera frame, all the things seems right. but my web test flash can’t show the correct video. Sometimes it seems correct, but when I re-click play button, it doesn’t show any picture on the flash.

  Here is my X264 config code

  x264_param_default_preset(&x264param, "ultrafast", "zerolatency");
  
  x264param.i_threads = 2;
  
  x264param.i_width = width;
  
  x264param.i_height = height;
  
  x264param.i_log_level = X264_LOG_DEBUG;
  
  x264param.i_fps_num = x264param.i_timebase_num= fps;
  
  x264param.i_fps_den = x264param.i_timebase_den=1;
  
  x264param.i_frame_total = 0;
  
  
  
  x264param.i_frame_reference =1;
  
  //x264param.i_frame_reference = 2;
  
  x264param.i_keyint_min = 25;
  
  x264param.i_keyint_max = fps*3;
  
  x264param.i_scenecut_threshold = 40;
  
  
  
  x264param.b_deblocking_filter = 1;
  
  x264param.b_cabac = 0;
  
  x264param.analyse.i_trellis = 0;
  
  x264param.analyse.b_chroma_me = 1;
  
  
  
  x264param.vui.i_sar_width = 0;
  
  x264param.vui.i_sar_height = 0;
  
  x264param.i_bframe_bias = 0;
  
  x264param.b_interlaced= 0;
  
  x264param.analyse.i_subpel_refine = 6; /* 0..5 -> 1..6 */
  
  x264param.analyse.i_me_method = X264_ME_DIA;//X264_ME_HEX?X264_ME_DIA
  
  x264param.analyse.i_me_range = 16;
  
  x264param.analyse.i_direct_mv_pred = X264_DIRECT_PRED_AUTO;
  
  x264param.i_deblocking_filter_alphac0 = 0;
  
  x264param.i_deblocking_filter_beta = 0;
  
  //x264param.analyse.intra = X264_ANALYSE_I4x4;
  
  x264param.analyse.intra = X264_ANALYSE_I4x4;//  | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16;
  
  x264param.analyse.inter = X264_ANALYSE_I4x4 | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16; 
  
  //edit 2014-7-28
  
  x264param.analyse.b_transform_8x8 = 1;
  
  //x264param.analyse.b_transform_8x8 = 0;
  
  x264param.analyse.b_fast_pskip = 1;
  
  x264param.i_bframe = 0;
  
  //x264param.b_intra_refresh
  
  x264param.analyse.b_weighted_bipred = 0;
  
  
  
  //// Intra refres:
  
  x264param.i_keyint_max = 250;
  
  x264param.b_intra_refresh = 0;
  
  ////Rate control:
  
  //x264param.rc.i_rc_method = X264_RC_CRF;
  
  
  
  //Rate Control
  
  x264param.rc.f_ip_factor = 1.4f;
  
  x264param.rc.f_pb_factor = 1.3f;
  
  x264param.rc.f_qcompress = 1.0;
  
  x264param.rc.i_qp_min = 20;//20;
  
  x264param.rc.i_qp_max = 32;
  
  x264param.rc.i_qp_step = 1;
  
  
  
  switch (0)
  
  {
  
  case 0: /* 1 PASS ABR */
  
      x264param.rc.i_rc_method = X264_RC_ABR;
  
      x264param.rc.i_bitrate = 300; // max = 5000
  
      x264param.rc.b_mb_tree = 0;
  
      break;
  
  case 1: /* 1 PASS CQ */
  
      x264param.rc.i_rc_method = X264_RC_CQP;
  
      x264param.rc.i_qp_constant = 26;//10 - 51
  
      break;
  
  }
  
  
  
  //For streaming:
  
  x264param.b_repeat_headers = 1;
  
  x264param.b_annexb = 1;
  
  x264_param_apply_profile(&x264param, "baseline");
  
  encoder = x264_encoder_open(&x264param);
  
  x264_picture_init( &pic_in );
  
  x264_picture_alloc(&pic_in, X264_CSP_I420, width, height);
  
  
  
  pic_in.img.i_csp = X264_CSP_I420|X264_CSP_VFLIP;
  
  pic_in.img.i_plane = 3;
  
  pic_in.i_type = X264_TYPE_AUTO;

  Sending To RTMP :

  sws_scale(convertCtx,&a,&scribe,0,height, pic_in.img.plane, pic_in.img.i_stride);
  
  int i_nal;
  
  int i_frame_size = x264_encoder_encode( encoder, &nal, &i_nal, &pic_in, &pic_out );
  
  if(i_frame_size <= 0){
  
      printf("\t!!!FAILED encode frame \n");
  
  }else{
  
      for (int i = 0,last=0; i < i_nal;i++)  
  
      {
  
          fwrite(nal[i].p_payload, 1, i_frame_size-last, fpw1);
  
          if (nal[i].i_type == NAL_SPS) {
  
              sps_len = nal[i].i_payload-4;
  
              sps  = new unsigned char[sps_len];
  
              memcpy(sps,nal[i].p_payload+4,sps_len);
  
          } else if (nal[i].i_type == NAL_PPS) {
  
              pps_len = nal[i].i_payload-4;
  
              pps  = new unsigned char[sps_len];
  
              memcpy(pps,nal[i].p_payload+4,pps_len);
  
              send_video_sps_pps(); 
  
              free(sps);
  
              free(pps);
  
          } else {
  
              send_rtmp_video(nal[i].p_payload,i_frame_size-last);
  
              break;
  
          }
  
          last += nal[i].i_payload;
  
      }
  
  }

  Send PPS and SPS

  void send_video_sps_pps(){
  
  if(rtmp!= NULL){
  
      RTMPPacket * packet;
  
      unsigned char * body;
  
      int i;
  
  
  
      packet = (RTMPPacket *)malloc(RTMP_HEAD_SIZE+1024);
  
      memset(packet,0,RTMP_HEAD_SIZE);
  
  
  
      packet->m_body = (char *)packet + RTMP_HEAD_SIZE;
  
      body = (unsigned char *)packet->m_body;
  
      i = 0;
  
      body[i++] = 0x17;
  
      body[i++] = 0x00;
  
  
  
      body[i++] = 0x00;
  
      body[i++] = 0x00;
  
      body[i++] = 0x00;
  
  
  
      /*AVCDecoderConfigurationRecord*/
  
      body[i++] = 0x01;
  
      body[i++] = sps[1];
  
      body[i++] = sps[2];
  
      body[i++] = sps[3];
  
      body[i++] = 0xff;
  
  
  
      /*sps*/
  
      body[i++]   = 0xe1;
  
      body[i++] = (sps_len >> 8) & 0xff;
  
      body[i++] = sps_len & 0xff;
  
      memcpy(&body[i],sps,sps_len);
  
      i +=  sps_len;
  
  
  
      /*pps*/
  
      body[i++]   = 0x01;
  
      body[i++] = (pps_len >> 8) & 0xff;
  
      body[i++] = (pps_len) & 0xff;
  
      memcpy(&body[i],pps,pps_len);
  
      i +=  pps_len;
  
  
  
      packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;
  
      packet->m_nBodySize = i;
  
      packet->m_nChannel = 0x04;
  
      packet->m_nTimeStamp = 0;
  
      packet->m_hasAbsTimestamp = 0;
  
      packet->m_headerType = RTMP_PACKET_SIZE_MEDIUM;
  
      packet->m_nInfoField2 = rtmp->m_stream_id;
  
  
  
      RTMP_SendPacket(rtmp,packet,TRUE);
  
      free(packet);   
  
      rtmp_start_time = GetTickCount();
  
  }else{
  
      std::cout<<"RTMP is not ready"<code>

  Send video Frame

  void send_rtmp_video(unsigned char * buf,int len){
  
  RTMPPacket * packet;
  
  long timeoffset = GetTickCount() - rtmp_start_time; 
  
  
  
  int type = buf[0]&0x1f;
  
  
  
  packet = (RTMPPacket *)malloc(RTMP_HEAD_SIZE+len+9);
  
  memset(packet,0,RTMP_HEAD_SIZE);
  
  
  
  packet->m_body = (char *)packet + RTMP_HEAD_SIZE;
  
  packet->m_nBodySize = len + 9;
  
  
  
  /*send video packet*/
  
  unsigned char *body = (unsigned char *)packet->m_body;
  
  memset(body,0,len+9);
  
  
  
  /*key frame*/
  
  body[0] = 0x27;
  
  if (type == NAL_SLICE_IDR) {
  
      body[0] = 0x17;
  
  }
  
  
  
  body[1] = 0x01;   /*nal unit*/
  
  body[2] = 0x00;
  
  body[3] = 0x00;
  
  body[4] = 0x00;
  
  
  
  body[5] = (len >> 24) & 0xff;
  
  body[6] = (len >> 16) & 0xff;
  
  body[7] = (len >>  8) & 0xff;
  
  body[8] = (len ) & 0xff;
  
  
  
  /*copy data*/
  
  memcpy(&body[9],buf,len);
  
  
  
  packet->m_hasAbsTimestamp = 0;
  
  packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;
  
  if(rtmp != NULL){
  
      packet->m_nInfoField2 = rtmp->m_stream_id;
  
  }
  
  packet->m_nChannel = 0x04;
  
  packet->m_headerType = RTMP_PACKET_SIZE_LARGE;
  
  packet->m_nTimeStamp = timeoffset;
  
  
  
  if(rtmp != NULL){
  
      RTMP_SendPacket(rtmp,packet,TRUE);
  
  }
  
  free(packet);

  }